1. Field of the Invention
The present invention relates to an air-conditioning system which performs air-conditioning, such as air-cooling, heating and dehumidification, and which is provided with an air cleaner capable of eliminating the dust and odorants from the air.
2. Description of the Related Art
An air-conditioning system performs air conditioning (such as air-cooling, heating and dehumidification) by drawing the air of a room into the heat exchanger of its indoor unit and performing heat exchange with respect to the drawn air.
An air-conditioning system recently developed is provided with an air cleaner which removes fine dust particles and odorants from the air circulated by the air-conditioning system. In this type of air-conditioning system, the air cleaner is made up of an electric dust-collecting device and an odorant filter device, and is arranged in front of the heat exchanger. The electric dust-collecting device includes a plurality of ionization wires connected to the positive terminal of a high d.c. voltage source. It also includes an electrode body having a plurality of electrode plates facing the ionization wires. The odorant filter device contains an activated carbon filter.
In general, it is desirable that the indoor unit of an air-conditioning system be installed on a wall portion close to the ceiling since the indoor unit installed at such a wall portion allows the floor space to be used effectively. It is also desirable that the indoor unit be as flat as possible since such a flat indoor unit does not give a feeling of oppression to the user.
Since the indoor unit installed on a wall portion close to the ceiling is limited in its vertical dimension, the heat exchanger incorporated in the indoor unit is also limited in its vertical dimension. Therefore, the heat exchanger is elongated in the widthwise direction of the indoor unit, so as to ensure a sufficiently wide heat exchange area. Accordingly, both the heat exchanger and the main body of the indoor unit are short in the vertical direction and are long in the horizontal direction.
If the air cleaner arranged in front of the heat exchanger has the same shape as the heat exchanger, it causes air resistance with reference to the heat exchanger. Because of this air resistance, the pressure loss of the air flowing into the heat exchanger increases, resulting in deterioration in the heat exchange efficiency of the air-conditioning system.
To solve this problem, the shape of the conventional air cleaner is determined in such a manner that its horizontal dimension is equal to that of the heat exchanger but its vertical dimension is half that of the heat exchanger. That is, the air cleaner is very long in the horizontal direction. If an air cleaner has such a shape, it does not cause much air resistance with reference to the heat exchanger. Thus, necessary heat exchange efficiency is ensured for the heat exchanger, and sufficient air cleaning efficiency is ensured for the air cleaner. The heat exchanger is fixed inside the main body of the indoor unit and has plates at the ends thereof. Both ends of the air cleaner are attached to the respective plates of the heat exchanger.
Although the air cleaner is very long, it is fixed only at the longitudinal ends. In other words, no support means is provided at an intermediate point of the air cleaner.
An air-conditioning system is transported after it is manufactured in a factory. During the transportation, vibration is applied to the air-conditioning system not only in the vertical direction thereof but also in the horizontal and diagonal directions. Since the air cleaner is fixed only at ends, as mentioned above, it bends during the transportation. In particular, its central portion greatly bends during the transportation. Due to this bending, the air cleaner may be damaged during the transportation. In the worst case, the air cleaner may be broken, or the portion for supporting the ionization wires of the electric dust-collection device may be deformed, resulting in disconnection of the ionization wires.
One measure for preventing this problem is to employ thick (therefore rigid) ionization wires. However, if thick ionization wires are used, the manufacturing cost of the air-conditioning system is increased, and the total weight of the air-conditioning system is also increased.
Another measure for preventing the problem is disclosed in Published Unexamined Japanese Patent Application No. 1-210045. According to this reference, a unit frame is provided with batten ribs, and these batten ribs are in contact with the heat exchanger. Due to the provision of the batten ribs, the distance between the unit frame and the heat exchanger is always maintained at a constant value. The distance remains unchanged even if the unit frame is pressed against the heat exchanger by an external force.
However, the vibration during the transportation does not always act in such a direction that the air cleaner is pressed against the heat exchanger. The heat cleaner is not only vibrated back and forth but also vibrated in the vertical and diagonal directions. The batten ribs may prevent the unit frame from touching the heat exchanger, but cannot suppress the vibration occurring in the other directions. Therefore, it is possible that the air cleaner will be deformed as a result of the vibration.